This invention relates to a scaffold having an electric drive for lifting a user, equipment, and materials from a ground level to an elevated working level within a contained area of height and width and to stabilize the scaffold on non-level ground, and mobility through interior passageways.
The homeowner and small commercial contractor struggle with small interior and exterior projects that are at elevated heights. They primarily rely are stepladders, stools, and extension ladders for these projects. The user must constantly travel up and down these structures to retrieve tools and materials. The work area is limited to the reach to the user. This places the user in an unsafe situation that may result in a fall from an elevated height. As the user leans to extend his reach, the ladder or stool may become unstable and tilt or the user may loose his grip or balance and fall to the ground. Also, the user needs to constantly reposition the structure as the work progress. This is very inefficient wasting precise time. Stability of the structure is also an issue when working on unleveled surfaces. This is a particular problem when outdoors.
Conventional aerial lifts are primarily designed for commercial and industrial users. The lifts initial purchase costs are high with significant reoccurring maintenance costs. The lifts employ hydraulics to elevate working platforms. The hydraulics requires significant maintenance and are constantly leaking making these machines unsuited for internal use for home or light industrial or small commercial operations. The relative size of the available machines also limits their use to external areas or internal spaces with wide doorways and high ceiling. Their use within a home or office is prohibited due to maneuverability through passageways and the leaking hydraulic fluid. Most conventional aerial lifts are powered by diesel engines, propane motors or large battery packs that also limits their usage within structures due to environment issues.
In order to work safety at elevated heights within a house or office for the purpose of installing or fixing electric fixtures, painting walls or ceiling, or changing light bulbs, it is necessary to have an apparatus that is lightweight, low cost, portable and mobile, anti-tilt, sufficient load lifting capabilities, compact design in full retracted position, transportable through doorways, platform work area sufficient to reduce up and down trips by operator, level mount features allow placement on non-level surfaces, and a motorized direct drive elevating means to eliminate the hydraulics.
Accordingly, several objects and advantages of my invention are to provide the consumer with a low cost, portable, mobile, multi-purpose scaffold for household use and light duty construction and maintenance.
It is a further object of this invention to provide a scaffold that is of lightweight construction with anti-tilt features.
It is a further object of this invention to provide a scaffold that has load-lifting capabilities up to 600 pounds.
It is another object of this invention to provide a scaffold that is compact in full-retracted position.
It is another object of this invention to provide a scaffold that is transportable through building doorways.
It is yet another object of this invention to provide a scaffold with a platform work area that limits up and down trips by operator.
It is a further object of this invention to a scaffold with level mount features that allow a scaffold to be placed on non-planar surfaces.
It is a further object of this invention to provide a scaffold with a motor direct drive system that eliminates oil leakages associated with hydraulic systems.
Still further objects and advantages will become apparent from a consideration of the ensuing description and accompanying drawings.
The objects set forth above as well as further and other objects and advantages of the present invention are achieved by the embodiments of the invention described hereinbelow.
Briefly stated, the preferred embodiment introduces an improvement in scissor advancement mechanism that enables significant reduction in the size of a lifting scaffold for multipurpose use. The present invention provides a means for lifting construction material, tools and workman to working heights within a confined working area. For example, one embodiment of the present invention provides a lifting platform of conventional design wherein the platform is lifted from ground level and maintained in a substantially level height by a known scissor arrangement. The invention is sized to allow transportation through household doorways and other limiting structures. The scissor arrangement raises a load by mechanical lifting means driven by at least on electric motor means powered by AC or DC power. Preferably the mechanical lifting means includes at least one ball screw. The ball screw is connected to the scissor arrangement such that as the electric motor rotates the screw, the scissors open and the platform raises. The present invention employs the advantages of using a mechanical drive rather than hydraulic fluid to elevate the platform.
An alternative embodiment includes electric micro switches provided in the assembly design to limit the extension and retraction position of the upper movable platform anywhere within a desired height range, preferably between 1 and 6.5 feet above surface level. These micro switches shut down electric power to the drive motor when mechanically activated.
Another alternative embodiment includes casters for maneuverability and allows the operator to transport the apparatus from location to location in similar manner to a dolly.
Yet another alternative embodiment includes stabilizing arms located on the stationary base to preclude the assembly from tipping over when the upper movable platform is fully extended. Leveling mounts located on the stabilizing arms allow the assembly to be mounted on non-level surfaces.
For a better understanding of the present invention, together with other and further objects thereof, reference is made to the accompanying drawings and detailed description and its scope will be pointed out in the appended claims.